JP2007336038A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal, not limited by a twofold mobile phone and a mobile terminal using a whip antenna, that can improve an antenna gain in making a speech, e.g. a left hand speech while tilting the mobile phone. <P>SOLUTION: The mobile terminal includes: a planar-shaped ground 1 with one end and the other end opposed to each other; an antenna 2 partially located at a corner direction of the one end of the ground 1 and connected to the ground 1; a ground extension section 9 partially located at a corner direction of the other end of the ground 1 and connected to the ground 1; a switch 8 interposed between the ground 1 and the ground extension section 9; a sensor 7 for detecting a tilt of the mobile terminal; and a control section 6 for controlling the switch 8 in response to the tilt of the mobile terminal detected by the sensor 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile terminal, and relates to a mobile terminal having an antenna.

  Antennas for mobile terminals, for example, antennas for mobile phones, have been increasingly built in the past few years due to portability and design. For the built-in antenna, a monopole antenna or an inverted F antenna having an electrical length of about λ / 4 of the communication radio wave is often used from the viewpoint of making the antenna volume small and thin. Among these, the monopole antenna of about λ / 4 is used for a mobile phone antenna because it needs to have a wide band and is relatively easy to downsize. There are various types of monopole antennas, and the monopole antenna is not limited to the above-described built-in antenna, and can be configured by a whip antenna, a helical antenna, or a meander antenna.

  When a whip antenna is used, the whip antenna is usually connected to the left end of the mobile phone in order to avoid an increase in the thickness of the mobile phone due to the overlap of the whip storage part and the wireless part of the mobile phone, the control part, the battery, etc. Or at the right end. In addition, the helical antenna and the meander antenna protruding to the upper part of the mobile phone have no problem of increasing the thickness as in the case of the whip antenna, but from the viewpoint of design, these are also the left end or right end of the mobile phone as in the case of the whip antenna. Placed in.

  Accordingly, an antenna feeding point for supplying a high-frequency current to an antenna, for example, a whip antenna, is provided not at the rectangular outer peripheral center of the mobile terminal but at the corner. This antenna feeding point also causes a high-frequency current to flow through a ground (for example, a rectangular substrate or shield in a mobile phone), and uses the ground as a part of the antenna. When a high-frequency current is passed over the ground, it flows from the antenna feed point toward the diagonal of the ground. As a result, the antenna is constituted by the whip antenna and the ground, and the antenna length (electric length) can be taken efficiently even if the cellular phone is small. For this reason, even in the built-in antenna, the antenna feeding point is often arranged at the left end or the right end of the mobile phone. Such a conventional mobile phone receives a communication radio wave having the same polarization direction as the direction represented by the vector composition of the direction of current flow on the whip antenna and the direction of current flow on the ground with a high antenna gain. can do.

  On the other hand, unlike a conventional fixed phone, a call on a mobile phone is not only dialed with the right hand and calling with the left hand, but may be dialed with the right hand and directly with the right hand. For this reason, it is necessary to obtain a good antenna characteristic, that is, a high antenna gain, regardless of which hand is used to talk. In order to solve this problem, Patent Document 1 provides two antennas so that communication radio waves can be received with high antenna gain in two directions, and the radio wave intensity received by each antenna is compared. A mobile phone that receives communication radio waves using the antenna is described. Patent Document 2 describes a mobile phone that receives communication radio waves with a high antenna gain in a plurality of directions by physically bending and deforming a whip antenna. Thus, a good antenna gain can be obtained during a call.

JP 2004-229048 A International Publication No. WO01-052349 Pamphlet

  However, the invention of Patent Document 1 has a problem that it can be used only with a folded cellular phone. Further, the invention of Patent Document 2 is effective only for a whip antenna that can be physically deformed such as bending, and cannot be used with a fixed helical antenna, meander antenna, or built-in antenna.

  The present invention has been made to solve the above-described problems, and is not limited to a half-folded mobile phone or a whip antenna. In the case of making a call by tilting a mobile phone, such as a left-hand call or a right-hand call. An object of the present invention is to obtain a portable terminal capable of improving antenna gain.

  A portable terminal according to the present invention includes a planar ground having one end and the other end facing each other, an antenna that is unevenly distributed in the corner direction of the one end and connected to the ground, and is unevenly distributed in the corner direction of the other end A ground extension connected to the ground, a switch interposed between the ground and the ground extension, a sensor for detecting a tilt of the mobile terminal, and a tilt of the mobile terminal detected by the sensor And a control unit for controlling the switch.

  According to the mobile terminal of the present invention, the antenna gain is not limited to a folded mobile phone or a whip antenna. For example, in a left-hand call, the antenna gain can be improved when the mobile phone is tilted to talk.

  Prior to describing the portable terminal according to the present invention, a conventional portable terminal will be described. In the following description, it is assumed that the mobile terminal is used for a mobile phone. FIG. 7 is a diagram showing a call (left hand call) with a conventional mobile phone held in the left hand. Only a typical configuration of the cellular phone is shown. For example, a ground 1 composed of a substrate and a shield in the cellular phone, and a whip antenna 2 that is an antenna that is provided unevenly in a corner direction of one end of the ground. And an antenna feeding point 4 for supplying a high frequency current to the ground 1 and the whip antenna 2.

  When making a phone call with a mobile phone in hand, as shown in FIG. 7, the mobile phone is often used at an angle of approximately 30 degrees from the horizontal direction. In a mobile phone configured and arranged in this way, a direction (dotted arrow) represented by a vector composition of the direction of current flow on the whip antenna (solid arrow) and the direction of current flow on the ground (solid arrow) The radio wave signal having the same polarization direction can be received with a high antenna gain. Similarly to FIG. 7, FIG. 8 shows a diagram in a case where a mobile phone is held in the right hand and a call is made (right hand call).

  Currently, the main polarization direction of communication radio waves transmitted from the base station is the vertical direction. However, as shown in FIG. 7 and FIG. 8, since the polarization direction in which both left-handed call and right-handed call can be received is not vertical, neither antenna gain is optimally obtained. bad. FIG. 9 shows a coordinate system and an antenna radiation pattern in the xz plane. The right hand call corresponds to “a. Antenna gain of right hand call” in the figure, and the left hand call corresponds to “b. Antenna gain of left hand call” in the figure. As described above, in the conventional mobile phone, the antenna gain is not optimally obtained in both the left-hand call and the right-hand call, but the right-hand call has a lower antenna gain than the left-hand call. Next, a mobile phone according to the present invention will be described.

<Embodiment 1>
FIG. 1 shows a rear view of the mobile phone according to the present invention and a view seen from the lower end of the mobile phone. The cellular phone according to the present invention is processed by a ground 1, a whip antenna 2, a ground 1 and an antenna feeding point 4 for supplying a high frequency current to the whip antenna 2, and an antenna feeding point 4, as shown in the figure. A radio unit 5 for bidirectionally converting a communication radio wave and an electric signal used for a mobile phone, a control unit 6, a gravity sensor 7, a switch 8 constituting a polarization improving means, and a ground extension unit 9. .

  As shown in the figure, the ground 1 is formed in a planar shape having one end and the other end facing each other. The ground 1 is composed of, for example, a substrate and a shield in a mobile phone. Whip antenna 2 as an antenna is unevenly distributed in the corner direction of ground 1 and connected to ground 1. In the present embodiment, whip antenna 2 is unevenly distributed at the left end of ground 1 and connected to ground 1. The whip antenna 2 is used as the antenna, but the present invention is not limited to this, and a helical antenna, meander antenna, inverted F antenna, or built-in antenna may be used.

  A gravity sensor (acceleration sensor) 7, which is a sensor for detecting the tilt of the mobile phone, detects the direction of gravity when stationary by a configuration that detects acceleration, for example, and detects the tilt of the mobile phone based on the direction. Here, when the mobile phone is tilted clockwise as shown in FIG. 7 from the arrangement of FIG. 1, the mobile phone is moved from the arrangement of FIG. 1 by detecting that gravity is working from the mobile phone to the right. Detects that the mobile phone is tilted clockwise. Similarly, when the mobile phone is tilted counterclockwise as shown in FIG. 8 from the arrangement shown in FIG. 1, the mobile phone is arranged as shown in FIG. 1 by detecting that gravity is working leftward from the mobile phone. To detect that the mobile phone is tilted clockwise.

  The polarization improving means is shown in FIG. As shown in the figure, the polarization improving means 3 includes a switch 8, a ground extension 9, and a ground removal 13. The ground extension 9 is unevenly distributed in the corner direction of the other end of the ground 1 and connected to the ground 1. Here, the ground extension portion 9 is diagonally distributed to the whip antenna 2 and connected to the ground 1. In the figure, the ground extension 9 is a rod-shaped conductor, but a conductive plate may be used if it is well designed.

  The switch 8 is interposed between the ground 1 and the ground extension 9. The ground punch 13 is an insulator, and for example, FR4 (Flame Retardant type 4), which is a printed board having no copper on the surface and inside thereof, is used. As shown in the figure, since the switch 8 and the ground extension 9 are formed on the ground removal 13, when the switch 8 is ON, the ground 1 and the ground extension 9 are electrically connected, and the ground extension A current also flows through the portion 9. When the switch 8 is OFF, the ground 1 and the ground extension 9 are not electrically connected, and no current flows through the ground extension 9. The switch 8 may be an SPDT switch, a PIN diode, a MEMS, or the like as long as it has a low resistance when turned on and a small capacity when turned off.

  The control unit 6 shown in FIG. 1 detects whether or not the mobile phone is in a call state, and controls the switch 8 according to the inclination of the mobile phone detected by the gravity sensor 7 during the call state. Specifically, when the gravity sensor 7 detects that the mobile phone is tilted clockwise as shown in FIG. 7 from the arrangement of FIG. 1, the control unit 6 performs control to turn on the switch 8. On the other hand, when the gravity sensor 7 detects that the mobile phone is tilted counterclockwise as shown in FIG. 8 from the arrangement of FIG. 1, the control unit 6 performs control to turn off the switch 8.

  With this configuration, in the case of a left-hand call, the gravity sensor 7 detects that the mobile phone is tilted clockwise, and the control unit 6 turns on the switch 8 accordingly. For this reason, the ground extension 9 is electrically added to the ground 1. In this case, the dimensions of the ground 1 are 100 mm in length, 40 mm in width, and 2 mm in thickness, the dimensions of the whip antenna 2 are 27 mm in length, φ1 mm, and an antenna for 2 GHz is configured, and the dimensions of the ground extension 11 are 10 mm in the x direction. When the y direction is 10 mm and φ1 mm, the antenna gain can be improved by 0.6 dB.

  On the other hand, in the case of a right-hand call, the gravity sensor 7 detects that the mobile phone is tilted counterclockwise, and the control unit 6 turns off the switch 8 accordingly. In this case, the radiation pattern is the same as the conventional one without the polarization improving means 3. Thus, according to the mobile phone according to the present embodiment, the antenna gain is not limited to a folded mobile phone or a whip antenna, and the same antenna gain as in the conventional case is maintained in a right-hand call, while the antenna gain can be improved in a left-hand call. did it.

<Embodiment 2>
FIG. 2 shows a rear view of the mobile phone according to the present invention and a view seen from the lower end of the mobile phone. As shown in the figure, the mobile phone according to the present invention is provided with a switch 10 and a ground extension portion 11 at positions different from them instead of the switch 8 and the ground extension portion 9 of the first embodiment. Therefore, in the present embodiment, configurations that are not newly described below are the same as those in the first embodiment.

  The polarization improving means 3 includes a switch 10, a ground extension 11, and a ground removal 13. Since the figure corresponding to this is a figure in which FIG. 4 is mirror-symmetrical, the numbers corresponding to the switch 10 and the ground extension 11 are superimposed and displayed in FIG. The same applies to FIGS. 5 and 6 below. The ground extension 11 is unevenly distributed in the corner direction of the other end of the ground 1 and is connected to the ground 1. In the present embodiment, as shown in FIG. 2, the ground extension 11 is unevenly distributed in the same direction as the whip antenna 2 and is connected to the ground 1. The switch 10 is interposed between the ground 1 and the ground extension 11. Similar to the operation of the switch 8, when the switch 10 is ON, the ground 1 and the ground extension 11 are electrically connected, and a current also flows through the ground extension 11. When the switch 10 is OFF, the ground 1 and the ground extension 11 are not electrically connected, and no current flows through the ground extension 11.

  The control unit 6 shown in FIG. 2 controls the switch 10 according to the inclination of the mobile phone detected by the gravity sensor 7. Specifically, when the gravity sensor 7 detects that the mobile phone is tilted clockwise as shown in FIG. 7 from the arrangement of FIG. 2, the control unit 6 performs control to turn off the switch 10. On the other hand, when the gravity sensor 7 detects that the mobile phone is tilted counterclockwise as shown in FIG. 8 from the arrangement of FIG. 2, the control unit 6 performs control to turn on the switch 10.

  With this configuration, in the case of a right-hand call, the gravity sensor 7 detects that the mobile phone is tilted counterclockwise, and the control unit 6 turns on the switch 10 accordingly. For this reason, the ground extension 11 is electrically added to the ground 1. In this case, when a 2 GHz antenna is configured using the ground 1 and the whip antenna 2 having the same dimensions as in the first embodiment, and the dimensions of the ground extension 11 are set to 20 mm in the -x direction, 10 mm in the y direction, and 1 mm in diameter. Was able to improve the antenna gain by 1.6 dB.

  On the other hand, in the case of a left-hand call, the gravity sensor 7 detects that the mobile phone is tilted clockwise, and the control unit 6 turns off the switch 10 accordingly. In this case, the radiation pattern is the same as the conventional one without the polarization improving means 3. Thus, according to the mobile phone according to the present embodiment, the antenna gain is not limited to the half-folded mobile phone and the whip antenna, and the same antenna gain as in the conventional case is maintained in the left hand call, while the antenna gain is improved in the right hand call. I was able to. Note that the antenna gain is greatly improved from that of the first embodiment because the direction in which the current flows in the ground 1 changes due to the current flowing in the ground extension portion 11, and the direction in which the current flows on the whip antenna. This is thought to be because vector synthesis is inclined in the direction of the center of gravity.

<Embodiment 3>
FIG. 3 shows a rear view of the mobile phone according to the present invention and a view seen from the lower end of the mobile phone. As shown in the figure, in the mobile phone according to the present invention, the ground extension is unevenly distributed in the same direction as the whip antenna 2 and is connected to the ground 1. The antenna 2 is configured to include a ground extension 11 that is a second ground extension connected to the ground 1 in a diagonally distributed manner. The switch includes switches 8 and 10 that are first and second switches interposed between the ground 1 and the ground extensions 9 and 11, respectively. In other words, both the switch 8 and the ground extension portion 9 of the first embodiment and the switch 10 and the ground extension portion 11 of the second embodiment are provided.

  The control unit 6 shown in FIG. 3 controls the switch 8 and the switch 10 according to the inclination of the mobile phone detected by the gravity sensor 7. Specifically, when the gravity sensor 7 detects that the mobile phone is tilted clockwise as shown in FIG. 7 from the arrangement of FIG. 3, the control unit 6 turns on the switch 8 and turns off the switch 10. Take control. On the other hand, when the gravity sensor 7 detects that the mobile phone is tilted counterclockwise as shown in FIG. 8 from the arrangement of FIG. 3, the control unit 6 turns off the switch 8 and turns on the switch 10. Do.

  The mobile phone configured as described above is the same as the state in which the switch 8 is turned on in the first embodiment in the case of a left-hand call, and the state in which the switch 10 is turned on in the second embodiment in the case of a right-hand call. Will be in the same state. As a result, when the antenna for 2 GHz is configured using the ground 1 and the whip antenna 2 having the same dimensions as in the first embodiment and the ground extension 9 having the same dimensions as in the first embodiment is provided, The antenna gain can be improved by 0.6 dB in a call. Furthermore, when the ground extension 11 having the same dimensions as in the second embodiment is provided, the antenna gain for right-handed calls can be improved by 1.6 dB. As described above, according to the mobile phone according to the present embodiment, the antenna gain can be improved in both the left-hand call and the right-hand call, without being limited to the folded mobile phone and the whip antenna.

<Embodiment 4>
FIG. 5 shows the configuration of the polarization improving means 3 of the mobile phone according to the present embodiment. In the present embodiment, a filter 12 that cuts off a current having a predetermined frequency is provided. In FIG. 5, a filter 12 that cuts off a current having a predetermined frequency is provided between the ground 1 and the switches 8 and 10. The position of the filter is not limited to the place shown in the figure, and the positions of the switches 8 and 10 and the filter 12 may be interchanged, and the filter 12 may be provided in the middle of the ground extension parts 9 and 11. In summary, a filter 12 that cuts off a current having a predetermined frequency is provided between the ground 1 and the free ends of the ground extensions 9 and 11. For example, the filter 12 includes a parallel resonant circuit that cuts off a current of 800 Hz in a dual-band mobile phone of 800 Hz / 2 GHz.

  With this configuration, since the 800 Hz current does not flow through the ground extensions 9 and 11, the antenna gain of the 800 Hz communication radio wave is the same as the conventional antenna, while the antenna gain is improved for the 2 GHz communication radio wave. be able to. Thus, in the case of receiving a 2 GHz communication radio wave, the influence of the 800 Hz communication radio wave can be relatively reduced by improving the antenna gain of the 2 GHz communication radio wave.

<Embodiment 5>
FIG. 6 shows the configuration of the polarization improving means 3 of the mobile phone according to the present embodiment. Unlike the embodiment described above, a switch 14 as a third switch is provided in the middle of the ground extension portions 9 and 11. The switch 14 controls the switches 8 and 10 in the same manner as in the above-described embodiment when, for example, an 800 Hz communication radio wave is used in a 800 Hz / 2 GHz dual band mobile phone. The switch 14 is turned on to lengthen the path of the current flowing through the ground extensions 9 and 11. On the other hand, when 2 GHz communication radio waves are used, the switches 8 and 10 are controlled in the same manner as in the above-described embodiment, and the switch 14 is turned off to reduce the current flowing in the ground extension portions 9 and 11. Shorten the route. The switch 14 may be an SPDT switch, a PIN diode, a MEMS, or the like as long as the resistance at the time of ON is low and the capacity at the time of OFF is small.

  If comprised in this way, according to the case where the communication electromagnetic wave to be used is either 800 Hz or 2 GHz, the length of the path | route of the electric current which flows in the ground extension parts 9 and 11 can be changed. Therefore, if the length of the current path is well designed so that the antenna gain is improved with respect to the frequency of each communication radio wave, the antenna gain can be improved at both frequencies of 800 Hz and 2 GHz. it can. In order to improve the antenna gain for a plurality of frequencies, a switch may be provided at a location corresponding to those frequencies.

It is the figure seen from the back view and the lower end which show the mobile phone which concerns on Embodiment 1. FIG. It is the rear view which shows the mobile telephone which concerns on Embodiment 2, and the figure seen from the lower end. It is the rear view which shows the mobile telephone which concerns on Embodiment 3, and the figure seen from the lower end. 3 is a diagram showing polarization improving means of the mobile phone according to Embodiment 1. FIG. 6 is a diagram showing polarization improving means of a mobile phone according to Embodiment 4. FIG. FIG. 10 is a diagram showing polarization improving means for a mobile phone according to a fifth embodiment. It is a figure which shows a mode when calling with a mobile phone with the left hand. It is a figure which shows a mode when calling with a mobile phone with the right hand. It is a figure which shows the radiation pattern of the conventional mobile telephone, and its coordinate axis.

Explanation of symbols

1 ground, 2 whip antenna, 3 polarization improving means, 4 antenna feeding point, 5 radio section, 6 control section, 7 gravity sensor, 8, 10, 14 switch, 9, 11 ground extension, 12 filter, 13 ground removal .

Claims (6)

A planar ground having one end and the other end facing each other;
An antenna unevenly distributed in the corner direction of the one end and connected to the ground;
A ground extension that is unevenly distributed in the corner direction of the other end and connected to the ground;
A switch interposed between the ground and the ground extension;
A sensor that detects the tilt of the mobile device,
A control unit that controls the switch according to the inclination of the mobile terminal detected by the sensor;
Mobile device. The ground extension is diagonally distributed to the antenna and connected to the ground.
The mobile terminal according to claim 1. The ground extension is unevenly distributed in the same direction as the antenna and connected to the ground.
The mobile terminal according to claim 1. The ground extension is
A first ground extension that is diagonally distributed to the antenna and connected to the ground; and a second ground extension that is unevenly distributed in the same direction as the antenna and connected to the ground.
The switch is
Including first and second switches respectively interposed between the ground and the first and second ground extensions;
The mobile terminal according to claim 1. A filter that cuts off a current having a predetermined frequency between the ground and a free end of the ground extension;
The portable terminal in any one of Claims 1 thru | or 4. A third switch in the middle of the ground extension;
The portable terminal in any one of Claims 1 thru | or 5.

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